The present invention relates to a centrifuge. More particularly this invention concerns a centrifuge having a centrifuge vessel whose wall and floor are separable for emptying out the device after use.
A centrifuge is known having an upwardly open cup-shaped vessel formed of a floor member and, separable therefrom, a generally cylindrically tubular wall member. The floor member is carried on the upper end of a shaft whose lower end is received in a heavy-duty bearing that permits limited canting of the shaft relative to its normal vertical axis. A motor is provided on this shaft for rotating the floor member at high speed about the upright axis of the shaft. When the wall member is resting on the floor member, usually by means of a downwardly flared frustoconical surface that mates with a corresponding surface of the floor member, this wall member is effectively entrained by the floor member.
The liquid phase of the material being centrifuged normally passes radially outwardly through one or more holes formed in the wall member. Immediately below this hole or these holes there is provided a deflecting flange which extends radially outwardly past the inner edge of an upwardly open trough. Thus the liquid exits radially over the flange and is captured in the trough.
In order to remove the solid phase after the material has been centrifuged, the wall member is normally provided with a radially outwardly extending peripheral flange which is engageable with a fixed ring within the housing of the centrifuge. The floor member is, therefore, lowered until this flange rests on the ring. Further lowering of the floor member will separate the two from each other so that the solid phase can be moved out through the annular gap formed between the coacting frustoconical support surfaces.
Such an arrangement has several problems. First of all it is necessary to locate the support bearing for the floor member relatively axially far from this floor member, as room must be provided for raising and lowering the floor member and for the motor that operates the centrifuge. Thus a long lever arm is provided for any unbalanced portions of the load to act on the support bearing. Particularly when the machine is rotating at high speed it is therefore possible for an unbalanced load to cause such wide swingings of the drum and floor member as to damage the apparatus. Another difficulty with this arrangement is that, in order to minimize the distance between the bearing and the floor member, the distance through which the floor member is displaceable in order to open the centrifuge is minimized. Relatively bulky objects being centrifuged, such as pieces of metal produced in machining operations and which are being centrifuged to degrease them, cannot move out of the centrifuge through the relatively narrow gap.
Finally, in case of failure of the support mechanism for the floor member, it is possible for this floor member to drop down and allow the load being centrifuged to move outwardly. Such failure can, therefore, result in severe damage to, if not total destruction of, the centrifuge.